


Anticipate, Retaliate

by peevee



Category: Sherlock (TV)
Genre: F/M, Fem!mycroft, Fingering, Genderswap, Pranks, Sibling Incest
Language: English
Status: Completed
Published: 2012-06-26
Updated: 2012-06-26
Packaged: 2017-11-08 14:37:09
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,724
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/444246
Author URL: https://archiveofourown.org/users/peevee/pseuds/peevee
Summary: <blockquote class="userstuff">
              <p>Sherlock winds his sister up, and Mycroft ups the game.</p><p>
  <i>There was a barely noticeable spot of blood directly in the centre of her bottom lip; she looked Sherlock in the eye before sliding her tongue out and slowly licking it off.</i>
</p>
            </blockquote>





	Anticipate, Retaliate

**Author's Note:**

> This was for a lovely kinkmeme prompt, [here](http://sherlockbbc-fic.livejournal.com/19743.html?thread=117413407#t117856031). The age gap here is 16/23, which could be underage depending on your country of origin. Also this story contains some mild gory parts, which you can avoid if you stop reading after _the sharp tones of his mother in return_ and start up again at _That evening before dinner_

“Mycroft has had sexual intercourse!”

“ _Sherlock_ ,” Mycroft slid her leg over his, digging her toenails into his foot in warning.

Mummy paused, spoon hovering over her grapefruit.

“She’s had it with a man _and_ a woman. More than once with the woman,” Sherlock continued, slipping his toe up the back of her calf.

Mummy closed her eyes, and let out a long sigh.

“Sherlock, go to your room.”

“But--”

“ _Sherlock_.” Her tone brooked absolutely no argument. “You may come out at lunch.”

He scuffed his way down the hall, smirking to himself as he heard Mycroft exclaim, “Mummy, I am twenty-three years old!” and the sharp tones of his mother in return. 

He spent the rest of the afternoon delicately pulling apart tendons from the leg of a cat he’d found dead in the dusty space underneath the shed. When he made to open his door at midday, he found the rest of the cat spread lavishly over the hallway carpet outside his room. With hindsight, perhaps storming into the kitchen with blood dripping down to his elbows hadn’t been the best way of proving his innocence. The maid fainted and had to be sent home and Sherlock was confined to his room, sans cat, for the rest of the day.

Mycroft tried and failed to hide her smile behind the pages of her book as he was led, protesting, up the stairs. There was a barely noticeable spot of blood directly in the centre of her bottom lip; she looked Sherlock in the eye before sliding her tongue out and slowly licking it off. Sherlock thought of it as he fucked up into his fist later.

-

That evening before dinner, Sherlock crept into Mycroft’s room and snipped holes in all of her stockings with barely contained glee. He slunk quietly into her library the next morning and watched her for almost two hours; her bare legs gleamed pale against the dark fabric of her favourite chair. Just before she got up to leave, she looked directly at him and pulled the fabric of her skirt up, up…

He turned away, face burning.

The anticipation of retaliation was almost as thrilling as the act itself, and he watched his sister all day, waiting. She ignored him.

The next morning, he made to pull on a pair of trousers to find that the legs had been expertly sewn shut. It was the same for every item of clothing he had brought with him from school. Mycroft’s eyes gleamed at him as he sat shivering in his pants and vest at the breakfast table, and she crossed her naked legs pointedly, gaze skipping over his long, coltish limbs. Sherlock pressed his ice-cold foot to her calf, making her squeal and jump. 

Mummy pressed her fingers to her eyes.

“Mycroft, I’m sure you’ll ensure that your brother has something appropriate to wear to dinner tonight? Black tie.”

Mycroft’s smile soured a little.

“Lucy has tools for unpicking; ensure that you use them properly.”

They unpicked the clothes together on the floor of Sherlock’s room, Sherlock in his pants and vest, Mycroft with her skirt crawling up her thighs. They worked in careful silence, broken occasionally by a soft hitch of breath.

-

At dinner, Sherlock plucked at a stray thread on his shirtsleeve that Mycroft had missed. The people seated around the table were _boring_ ; Mycroft was _boring_. He elbowed her slightly, and she shifted away from him round the corner of the table, pretending to look interested in what her portly moustachioed neighbour was saying. He was mostly waffling complete nonsense, more interested in looking down her sheer blouse than anything else, but she laughed indulgently at whatever trite joke he had just made. He looked like a great fat walrus. Sherlock turned away in disgust, picking at his braised pigeon and chewing absentmindedly. Mycroft was still ignoring him. Infuriating. He could see the delicate lacy edge of her bra through her blouse.

He slid his left hand under the table and pinched her bare leg; she jumped a little but smoothly continued her conversation with the walrus. He pinched a little harder, but this time there was absolutely no reaction. He took a petulant bite of salad. His hand was still resting on her thigh below the demure hem of her skirt, and he smirked against his fork as he tickled her leg in a soft little circle, making her breath catch in her throat mid-sentence. The walrus didn’t seem to notice, and Sherlock tickled a little higher, pushing her skirt upwards. She shifted.

He flexed his fingers against her skin again, just a little, and she let out a sigh and slowly parted her thighs in unmistakable invitation. 

Sherlock froze. 

He glanced again at his sister, but her face was impassive. It was possible that there was a tiny hint of a smirk hovering on her lips but it could have been his imagination. His hand trembled against her skin and he stayed there for several seconds, unsure of his next move. 

The moustachioed walrus guffawed at something Mycroft was saying, suddenly. She giggled in return, and Sherlock slid his hand abruptly up under her skirt, making the end of her giggle sound rather choked. Wasn’t that satisfying. He trailed a hesitant finger against the edge of her underwear, trying to listen to the sound of her breathing over the pounding of his own heart. It came slightly shakily, and Sherlock felt his heart like it was going to beat right out of his ribcage. He stroked the slightly scalloped edge of her knickers again, lightly, and she parted her legs further, hooking one of her calves over his. He was already half-hard, and he swallowed thickly, concentrating on stilling the shaking of his fingers so he could hook them gently under the elastic.

“Sherlock!”

He managed not to jump, and his hand remained where it was, hot and damp. He felt Mycroft shift a little against his fingers, brushing them briefly against soft, curling hair. His mother gazed at him expectantly.

“Sorry Mummy, what?” he managed.

“Don’t pick at your food, Sherlock, it’s not polite.” She frowned, “If you’re finished, ask to be excused from the table.”

Mycroft dug her foot painfully into his leg, and he stabbed his fork into a piece of pigeon obligingly, raising his eyebrows at his mother. She turned back to the woman seated next to her with a sigh.

Softly, he edged his fingers further under the elastic of Mycroft’s knickers. Heart pounding, he allowed one of his fingers to slip downwards slightly. It was wet. Wet and hot. Heat pooled in his stomach, and his cock twitched where it lay heavy against his thigh. He spread his fingers as best he could with his limited manoeuvrability and stroked them slippery against her. Against his calf, her toes curled. She laughed--a little shakily, he thought--at something the walrus said.

He edged forwards in his seat a little to get a better angle, unseeingly pushing salad around on his plate as he slanted his fingers. He pressed a little, and with a sudden stunning rush they slid deeply into her, and _fuck_ , the _heat_ was all he could register for a second. Heat, and the way Mycroft was trembling almost imperceptibly, the way she clenched flutteringly around him. He closed his eyes, biting his lip.

He’d read about this, but the anatomical texts with disembodied diagrams, arrows and annotations and clinical language hadn’t mentioned how _wet_ , how _hot_. He curled his hand hesitantly, amazed at the immediate tightening around his soaked fingers. _God_. He pulled them out slowly, eager to explore a little more. 

He glanced up at his sister; aside from a hectic pink flush on her face (easily attributed to the warmth of the room) she looked completely impassive. The walrus had turned his attention elsewhere and she had turned to pick delicately at her own bird, pulling the dark meat from the bone with long, pale fingers. She glanced over at him and their eyes met, want gathering thick and warm in his throat. Her pupils were absolutely huge. He swallowed with an audible click, and he felt as Mycroft spread her legs wider still, brazen under the busy table.

He looked down at his plate, willing away the heat that prickled up his spine, threatening to spill onto his face. Mycroft squirmed a little. 

Sherlock moved his hand again, cataloguing. He rubbed her softly ( _labium minus_ ) between his fingertips, drew his fingers up to stroke her ( _clitoral prepuce, clitoral glans—oh_ ) and she stiffened, eyelids fluttering shut for a second. He flicked his fingers, gradually gaining an exploratory rhythm, feeling with fascination as she got wetter and wetter. The erectile tissue of her clitoris swelled almost imperceptibly, but just enough for him to feel with the sensitive tips of his fingers. Her breathing lost regularity, becoming stilted and shivery and her toes curled and uncurled against the fine wool blend of his trousers. He was so engrossed that he almost missed the way her foot jerked suddenly against his calf and she let out a tiny, quiet noise, which she quickly covered with a cough. She had orgasmed, right there at the table. 

Sherlock was swept with the sudden urge to grab her, throw her on the floor and push his cock straight into her where he knew she was hot and slick. It was almost overwhelming, and he flexed his fingers even as she squirmed away from them, imagining holding her down by her slim hips and spreading her thighs open. He closed his eyes, breathing heavily.

With a steadying breath, he turned his attention back to the table; still full of chattering insipid guests, none of them any the wiser. His pigeon lay cold on the plate. With a tiny, wet sound he pulled his fingers free from his sister’s knickers and gazed directly at her as he slid them slowly into his mouth. She tasted sharp, dark and salty, and he sucked on them until his mother scolded him absently for eating with his fingers. 

Later, in the dark, he pushed them back into his mouth, and thought of the slow smile that had spread on Mycroft’s face. The one that meant he’d impressed her. 

He waited for the knock.


End file.
